As a conventional infrared detection element, these are one wherein a piezoelectric element utilizing piezoelectric effect is employed, one wherein a thermopile obtained by integrating thermocouples is employed, and the like ones. These infrared detection elements have been used widely, since they have the following characteristic features such as:
(a) Cooling is not necessary. PA1 (b) There is no wavelength dependency in sensitivity. PA1 (c) They can be manufactured inexpensively in comparison with the other elements.
However, since repsonse time of these infrared detection elements is slow, i.e. it ranges from several tens milliseconds to several hundreds milliseconds, they could not have been used for such applications which require quick speed of response. Furthermore, since these conventional elements can detect only one point by one element, there is a limit as to detection of a position of an infrared source by means of the elements combined, In addition, these elements are not satisfactory in view of cost.